Medical Diagnosis Process and Investigations

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Questions and Answers

What is the first step in the diagnostic process?

Differential Diagnosis

History (correct)

Investigations

Examination

Which of the following is NOT a purpose of laboratory investigations?

Screening

Prognosis

Directly treating the condition (correct)

Monitoring treatment

Why is it important to consider the clinical context when interpreting laboratory results?

To maximize the number of tests performed

To simplify the diagnosis process

To avoid unnecessary risk and false positives (correct)

To ensure tests are selected randomly

When should investigations be requested?

After a clinical assessment of the patient Signup and view all the answers

What is the approach to selecting laboratory investigations?

Begin with the least invasive and risky options Signup and view all the answers

Which of the following is an essential aspect of suitable investigations?

Accuracy and relevance to the clinical situation Signup and view all the answers

What is the primary focus of differential diagnosis in the diagnostic process?

To narrow down potential diagnoses based on symptoms Signup and view all the answers

What can lead to unnecessary risks and costs in diagnostic testing?

Performing irrelevant investigations Signup and view all the answers

What is the role of albumin in the blood?

Major component of blood protein made by the liver Signup and view all the answers

Which blood test would most likely show elevated levels in patients with liver damage?

Aminotransferases Signup and view all the answers

What does a high level of bilirubin in the blood typically suggest?

Liver disease Signup and view all the answers

Which condition can cause increased potassium levels in the blood?

Renal impairment Signup and view all the answers

What does the estimated glomerular filtration rate (eGFR) indicate?

Kidney function Signup and view all the answers

What can histopathology detect?

Cellular changes such as metaplasia and neoplasia Signup and view all the answers

Which measurement would indicate anemia in a blood count?

Low haemoglobin (Hb) concentration Signup and view all the answers

Which component is primarily tested to understand the structural integrity of liver cells?

Alkaline phosphatase Signup and view all the answers

What type of samples are commonly used for microbiological testing?

Swabs, body fluids, and biopsies Signup and view all the answers

What is the purpose of biochemical profiling in microbiology?

To provide a more precise identification of isolates Signup and view all the answers

Which statement correctly describes a characteristic of antigen detection tests?

They depend on the presence of antibodies against the antigens. Signup and view all the answers

What is the main advantage of Polymerase Chain Reaction (PCR) in diagnostics?

It allows for the exponential replication of specific DNA sequences. Signup and view all the answers

Why is understanding reference ranges important in laboratory testing?

To interpret results in a clinical context accurately. Signup and view all the answers

Which of the following is a limitation of lab test results?

They may not accurately reflect the clinical status of a patient. Signup and view all the answers

What role do primers play in PCR?

They serve as the starting point for DNA synthesis. Signup and view all the answers

What is the primary use of culture media in microbiological testing?

To selectively grow certain types of bacteria. Signup and view all the answers

What type of cells primarily compose the secretory portion of major salivary glands?

Acinar cells Signup and view all the answers

What is the function of myoepithelial cells in salivary glands?

Compress acini to aid in saliva secretion Signup and view all the answers

What type of epithelium lines the small intercalated ducts of salivary glands?

Simple cuboidal Signup and view all the answers

How is the electrolyte concentration of initial saliva relative to plasma?

It is isotonic Signup and view all the answers

What occurs during the ductal modification of saliva?

Net absorption of solute, specifically sodium chloride Signup and view all the answers

What is the relationship between saliva flow rate and bicarbonate concentration?

Bicarbonate concentration increases with increasing flow rate Signup and view all the answers

What is the tonic nature of resting saliva compared to stimulated saliva?

Very hypotonic for resting, less hypotonic for stimulated Signup and view all the answers

Which type of gland is classified as a compound tubuloacinar gland?

Major salivary glands Signup and view all the answers

Which of the following conditions can cause dysphagia related to the mouth?

Mouth cancer Signup and view all the answers

What neurologic condition is specifically mentioned as a cause of dysphagia?

Parkinson's disease Signup and view all the answers

Identify a gastrointestinal condition that can contribute to dysphagia.

Oesophageal cancer Signup and view all the answers

Which method is commonly used for assessing swallowing difficulty?

Barium swallow test Signup and view all the answers

What is a common feature of pharyngeal dysphagia causes?

Mediastinal tumour Signup and view all the answers

Which assessment technique is considered a clinical assessment for swallowing?

Bedside swallow test Signup and view all the answers

Which of these conditions is associated with the oesophagus causing dysphagia?

Oesophageal strictures Signup and view all the answers

During which phase of swallowing is the lower oesophageal sphincter involved?

Esophageal phase Signup and view all the answers

What are the primary roles of taste receptor cells?

Detect chemical signals Signup and view all the answers

Which of the following is NOT a phase of swallowing?

Gastric phase Signup and view all the answers

What structure prevents the reflux of gastric contents into the oesophagus?

Lower oesophageal sphincter Signup and view all the answers

What is the function of mastication in the digestive process?

Physical breakdown of food Signup and view all the answers

Which part of the pharynx is located posterior to the nasal cavity?

Nasopharynx Signup and view all the answers

During which phase of swallowing is the epiglottis involved?

Pharyngeal phase Signup and view all the answers

What role do microvilli play in taste receptor cells?

Increase surface area Signup and view all the answers

Which of the following symptoms is commonly associated with gastro-oesophageal reflux disease (GORD)?

Heartburn Signup and view all the answers

What initiates the involuntary swallowing reflex?

Somatosensory receptors Signup and view all the answers

What structure connects the larynx to the oesophagus?

Pharynx Signup and view all the answers

What causes water to move out of plasma and into a solution with higher osmolarity?

Osmotic pressure differentials across a membrane Signup and view all the answers

Which type of cells in the salivary glands are responsible for the primary secretion of saliva?

Acinar cells Signup and view all the answers

What happens to saliva during ductal modification?

Potassium and bicarbonate concentrations increase Signup and view all the answers

How does stimulation of the parasympathetic nervous system affect saliva composition?

Saliva contains more enzymes Signup and view all the answers

What role do sodium-hydrogen exchangers play during ductal modification of saliva?

They remove sodium from the saliva Signup and view all the answers

What is the effect of increased saliva flow rate on ductal modification?

Less ductal modification occurs Signup and view all the answers

Which of the following statements is true regarding taste receptor cells?

They are chemoreceptors Signup and view all the answers

What happens to sodium and chloride absorption in the salivary ducts?

Sodium absorption is greater than chloride absorption Signup and view all the answers

What does osmolarity measure in a solution?

The concentration of osmotically active particles per litre of solution Signup and view all the answers

When two solutions are isotonic, what occurs?

There is no net movement of water Signup and view all the answers

What property of a solution defines its tonicity?

How it affects water movement across a semi-permeable membrane Signup and view all the answers

How is saliva categorized in relation to normal plasma?

Hypotonic Signup and view all the answers

Which gland primarily secretes serous saliva rich in α-amylase?

Parotid gland Signup and view all the answers

What is not found in high concentration in saliva?

Sodium (Na+) Signup and view all the answers

What role do antibacterial agents in saliva, like lysozyme and antibodies, serve?

To combat bacteria and prevent infections Signup and view all the answers

Which characteristic distinguishes exocrine glands from other types?

They have ducts that lead to the surface of an organ. Signup and view all the answers

What is the definition of malnutrition?

A diet lacking sufficient nutrients or the correct balance of nutrients Signup and view all the answers

Which macronutrients are primarily discussed in relation to their function in health?

Proteins, carbohydrates, and fats Signup and view all the answers

What is an essential component of good nutrition aside from a balanced diet?

Regular physical activity Signup and view all the answers

Which of the following best describes good nutrition?

An adequate and well-balanced diet Signup and view all the answers

What is the primary focus of healthy eating as mentioned in the learning outcomes?

Understanding major food groups and their dietary contributions Signup and view all the answers

What is the recommended daily intake of folate for women prior to pregnancy?

400 µg/day Signup and view all the answers

What condition is primarily caused by Vitamin C deficiency?

Scurvy Signup and view all the answers

What is the main source of Vitamin D for humans?

Sunlight Signup and view all the answers

What significant health issue can result from Vitamin D deficiency in children?

Rickets Signup and view all the answers

Which of the following is a common cause of iron deficiency anemia?

Heavy menstrual bleeding Signup and view all the answers

What is a common cause of hypocalcemia?

Renal disease Signup and view all the answers

Which mineral is essential for oxygen transport in the body?

Iron Signup and view all the answers

What happens to the skin's ability to synthesize Vitamin D as people age?

It decreases Signup and view all the answers

Which food source is high in potassium?

Fruits Signup and view all the answers

What is the role of Vitamin D in bone health?

Regulates calcium levels Signup and view all the answers

What is the primary function of carbohydrates in the diet?

Energy source and metabolism control Signup and view all the answers

Which of the following options describes lipids?

They store energy and aid in digestion Signup and view all the answers

What is the formula used to calculate the Basal Metabolic Rate (BMR) for women?

BMR Women = 655.1 + (9.563 * weight [kg]) + (1.85 * height [cm]) − (4.676 * age [years]) Signup and view all the answers

What is the energy content of proteins?

4 kcal/g Signup and view all the answers

How much energy (kcal) is obtained from fat if a pie contains 9.4 grams of fat?

84.6 kcal Signup and view all the answers

What percentage of the pie's energy content is derived from fat if total energy is 218 kcal?

39% Signup and view all the answers

What is the classification of vitamins that are required in small quantities?

Micronutrients Signup and view all the answers

Which vitamin is essential for collagen synthesis?

Vitamin C Signup and view all the answers

In terms of energy balance, what implies stable weight?

Calories in = calories out Signup and view all the answers

What is folate particularly important for?

Cell division and DNA synthesis Signup and view all the answers

What percentage of daily energy requirement does 84.6 kcal represent for a woman with a guideline of 2000 kcal?

4.23% Signup and view all the answers

Which vitamin is primarily derived from sunlight?

Vitamin D Signup and view all the answers

Which of the following conditions is NOT associated with the treatment of hypoparathyroidism?

Chronic liver disease Signup and view all the answers

What is the calculation to determine the percentage of energy from fat for men if their daily requirement is 2500 kcal?

$84.6 ÷ 2500 x 100$ Signup and view all the answers

What defines the chemical name of Vitamin K?

Phylloquinone Signup and view all the answers

What roles do the basal metabolic rate (BMR) calculations serve in energy expenditure?

Estimating energy needs at rest Signup and view all the answers

What is a common source of Vitamin B12?

Fish and dairy Signup and view all the answers

What is the main role of water-soluble vitamins?

To support metabolic processes Signup and view all the answers

What are hormones specifically responsible for in the body?

Regulating a variety of activities throughout the body Signup and view all the answers

Which of the following glands produces insulin?

Pancreas Signup and view all the answers

What type of hormone includes insulin and glucagon?

Proteins and polypeptides Signup and view all the answers

Which hormone is produced by the hypothalamus?

Antidiuretic hormone Signup and view all the answers

What is the primary function of thyroid hormones?

Promoting metabolic processes Signup and view all the answers

Which hormone is primarily associated with male characteristics and sperm production?

Testosterone Signup and view all the answers

What is the role of hormones in relation to specific receptors?

To initiate signals only in target cells with high-affinity receptors Signup and view all the answers

Which of the following hormones is produced by the adrenal glands?

Epinephrine Signup and view all the answers

Which feedback mechanism is most commonly applied for regulating hormone secretion?

Negative feedback Signup and view all the answers

What hormone is released in response to a decrease in serum Ca2+ concentration?

Parathyroid hormone (PTH) Signup and view all the answers

What is a characteristic of positive feedback compared to negative feedback in hormone regulation?

It is explosive and self-reinforcing. Signup and view all the answers

What is the function of the hormone-receptor complex after it enters the nucleus?

To dimerize and act as a transcription factor Signup and view all the answers

Which of the following groups is NOT produced by the adrenal cortex?

Peptide hormones Signup and view all the answers

What process allows water-soluble hormones to affect cellular function?

Binding to surface cell-membrane receptors Signup and view all the answers

What is the primary function of adrenocorticotropic hormone (ACTH)?

Stimulates the adrenal cortex to secrete corticosteroids Signup and view all the answers

What is the outcome of the process initiated by steroid hormones binding to their receptors?

Synthesis of new proteins through mRNA Signup and view all the answers

Which hormone surge precedes ovulation as a result of positive feedback?

Luteinizing hormone (LH) Signup and view all the answers

How does the endocrine gland respond when it senses a regulated variable is too high?

By decreasing the rate of hormone secretion Signup and view all the answers

Which class of hormones does the adrenal cortex produce that affects body minerals?

Mineralocorticoids Signup and view all the answers

How does parathyroid hormone affect serum calcium levels?

It increases serum calcium levels. Signup and view all the answers

Which of the following describes the role of G proteins in hormone action?

Initiating a cell-signaling pathway Signup and view all the answers

What is produced as a result of the transcription initiated by steroid hormone-receptor dimers?

Messenger RNA Signup and view all the answers

What role do protein kinases play in hormone signaling pathways involving water-soluble hormones?

Phosphorylating proteins in the cytoplasm Signup and view all the answers

What physiological action does aldosterone induce in the renal principal cells?

Synthesis of Na+ channels Signup and view all the answers

What triggers the secretion of aldosterone?

Elevated blood K+ levels Signup and view all the answers

What is the primary function of cortisol as a glucocorticoid?

Inhibiting tissue building Signup and view all the answers

Which hormone is primarily responsible for fluid and electrolyte balance?

Aldosterone Signup and view all the answers

What is the source of ACTH secretion?

Anterior pituitary gland Signup and view all the answers

What process do glucocorticoids primarily promote to maintain fuel supplies during stress?

Gluconeogenesis Signup and view all the answers

Which of the following is a precursor to ACTH?

Proopiomelanocortin (POMC) Signup and view all the answers

What role does aldosterone play in the kidneys?

Enhances sodium retention Signup and view all the answers

What effect do glucocorticoids have on adipose tissue?

Decrease insulin sensitivity Signup and view all the answers

What is the primary function of an endocrine gland?

To produce and secrete hormones directly into the bloodstream Signup and view all the answers

Which term describes a substance secreted by a cell that acts on adjacent cells?

Paracrine Signup and view all the answers

What is the key difference between primary and secondary endocrine dysfunction?

Primary dysfunction is due to glandular issues, while secondary is due to external factors Signup and view all the answers

What is a hormone?

A molecule that regulates cell activity at distant sites Signup and view all the answers

Which process is crucial for maintaining homeostasis in the endocrine system?

Negative feedback mechanisms Signup and view all the answers

Which of the following is a characteristic of exocrine glands?

They release their products through ducts onto epithelial surfaces Signup and view all the answers

What does autocrine signaling refer to?

Substances secreted by a cell that act on the same cell Signup and view all the answers

Which characteristic is NOT a function of hormones?

Directly initiating nerve impulses Signup and view all the answers

What is the general molecular formula for carbohydrates?

[C(H2O)]n Signup and view all the answers

Which type of carbohydrate consists of two monomeric units?

Disaccharides Signup and view all the answers

What physiological roles do lipids serve?

Energy source and hormonal signaling Signup and view all the answers

What defines monosaccharides?

They contain a single monomeric unit Signup and view all the answers

Which of the following carbohydrate classifications includes more than ten monomeric units?

Polysaccharides Signup and view all the answers

What structural feature characterizes polysaccharides?

They cannot be absorbed directly Signup and view all the answers

What are the general roles of carbohydrates in biological processes?

Energy source Signup and view all the answers

Which of the following best describes isomers?

They contain the same atoms arranged differently Signup and view all the answers

Which of the following monosaccharides is a hexose?

Galactose Signup and view all the answers

What type of bond is formed when two monosaccharides react to form a disaccharide?

Glycosidic bond Signup and view all the answers

Which of the following statements is true regarding fatty acids?

Fatty acids can be saturated or unsaturated. Signup and view all the answers

What is the primary type of carbohydrate found in starch?

Amylopectin Signup and view all the answers

What forms when a ketone body is produced in the liver?

Water-soluble fatty acids Signup and view all the answers

Which of the following is a major role of lipids in the body?

Serve as fuels for energy metabolism Signup and view all the answers

What type of ring do hexoses typically form?

Six-membered ring Signup and view all the answers

Which of the following fatty acids is described as a ω-9 fatty acid?

Oleic acid Signup and view all the answers

Which disaccharide consists of glucose and fructose?

Sucrose Signup and view all the answers

What is a characteristic of cis fatty acids compared to trans fatty acids?

Cis fatty acids pack next to each other less closely. Signup and view all the answers

Which structure is crucial for the assembly of cellular membranes?

Phospholipids Signup and view all the answers

What is the primary component of RNA?

Ribose Signup and view all the answers

What type of polymer is cellulose considered?

Linear polymer Signup and view all the answers

Which ketone body is not a product formed in the liver during fasting?

Glucose Signup and view all the answers

What is the primary role of lipoproteins in the body?

Transportation of lipids Signup and view all the answers

Which of the following describes oxidation in organic molecules?

Loss of electrons Signup and view all the answers

What characterizes a lipoprotein with the highest triglyceride content?

Delivers dietary triglycerides to peripheral tissues Signup and view all the answers

What is the function of lipoprotein lipase?

Releases fatty acids from lipoproteins Signup and view all the answers

Which glucose transporter is insulin-sensitive?

GLUT-4 Signup and view all the answers

What type of transport does SGLT-1 primarily utilize?

Secondary active transport Signup and view all the answers

What determines the density classification of lipoproteins?

Amount of triglycerides and cholesterol Signup and view all the answers

Which glucose transporter has the highest affinity for glucose?

GLUT-1 Signup and view all the answers

What type of molecules are released from chylomicrons by lipoprotein lipase?

Fatty acids Signup and view all the answers

What is the consequence of a high level of oxidized organic molecules in the body?

Greater potential for energy release Signup and view all the answers

What is the primary function of HDL in the body?

Remove cholesterol from tissues Signup and view all the answers

Which of the following describes the hydrophilic surface of lipoproteins?

Phospholipids and proteins Signup and view all the answers

What is the relationship between oxidation and reduction reactions?

Oxidation removes electrons, reduction adds electrons Signup and view all the answers

In which tissue is GLUT-2 primarily located?

Liver and pancreatic β-cells Signup and view all the answers

What is a major limitation of self-reported dietary histories?

Information can be difficult to obtain or may be misreported. Signup and view all the answers

What is one way individual perceptions of dietary norms can differ?

Cultural backgrounds can influence views on nutrition. Signup and view all the answers

Why is it challenging to obtain an accurate dietary history?

The 24-hour recall may not be representative of usual intake. Signup and view all the answers

What aspect is critical when advising on healthy eating?

Knowing where to refer for expert advice. Signup and view all the answers

Which of the following best explains the importance of a healthy diet for homeostasis?

A healthy diet helps maintain normal biological processes. Signup and view all the answers

What challenge might someone face in maintaining a healthy diet according to the biopsychosocial model?

Social pressures may discourage healthy eating. Signup and view all the answers

When gathering dietary history, which question could provide relevant information about typical eating patterns?

Was yesterday a typical eating day for you? Signup and view all the answers

What might prevent a client from sharing their dietary habits during a consultation?

Fear of being judged or experiencing stigma. Signup and view all the answers

What principle focuses on acting in the patient's best interests?

Beneficence Signup and view all the answers

Which perspective emphasizes the importance of trust in healthcare?

Family Signup and view all the answers

What ethical theory involves weighing a patient's interests against the benefits of training the student?

Consequentialism Signup and view all the answers

What should be considered when evaluating the harms associated with a procedure performed by a medical student?

The experience level of the student Signup and view all the answers

What is one potential concern of other patients regarding medical student training?

They might feel they are part of an experiment Signup and view all the answers

What is the main distinction between facts and values in healthcare?

Facts are based on empirical methods, while values are subjective beliefs. Signup and view all the answers

Which ethical principle is particularly relevant when considering a patient's autonomy?

Respect for autonomy Signup and view all the answers

In Maria's case, what value does she prioritize in her decision not to undergo a heart transplant?

The avoidance of suffering and maintaining her own identity. Signup and view all the answers

How do contextual factors influence ethical decision-making in healthcare?

They can modify the application of ethical theories to specific cases. Signup and view all the answers

Which ethical theory focuses on the outcomes of actions to determine their morality?

Utilitarianism Signup and view all the answers

What role do doctors often play in the ethical decision-making process regarding treatment?

They provide information and recommendations while respecting patient choices. Signup and view all the answers

Which factor is least likely to be considered when making ethical decisions in healthcare?

The popularity of the treatment among healthcare professionals. Signup and view all the answers

What is a primary ethical consideration in Maria's situation regarding her heart transplant?

Her personal right to refuse treatment. Signup and view all the answers

What is the primary focus of utilitarianism in ethical decision-making?

Maximizing pleasure and minimizing suffering Signup and view all the answers

What principle is foundational to deontological ethics?

Moral rules must be followed regardless of outcomes Signup and view all the answers

In virtue ethics, what is the main consideration when determining the right action?

The type of person one should strive to be Signup and view all the answers

What does the phrase 'virtue lies in a mean' refer to in virtue ethics?

Achieving moderation between excess and deficiency Signup and view all the answers

How do utilitarian, deontological, and virtue ethics differ in their approach to helping others?

Utilitarian focuses on outcomes, deontologist on rules, virtue ethicist on personal character Signup and view all the answers

What is the correct order of elements to consider in ethical reasoning according to the PPP framework?

Principles, Particulars, Perspectives Signup and view all the answers

What is the significance of the statement 'the right is prior to the good' in deontological ethics?

Adhering to moral rules is paramount, irrespective of the results Signup and view all the answers

In clinical ethical practice, which of the following is NOT a component of the ethical reasoning framework?

Purposes Signup and view all the answers

What are thick concepts characterized by?

Having both factual and evaluative content Signup and view all the answers

How should factual statements be assessed?

Through empirical methods Signup and view all the answers

Which moral theory focuses on the consequences of actions?

Utilitarianism Signup and view all the answers

What is a key principle of consequentialism?

The evaluation of actions based on their consequences Signup and view all the answers

What is a limitation of defining 'best consequences' in consequentialism?

It leaves the criteria for evaluation unclear Signup and view all the answers

What does utilitarianism specifically maximize?

Utility Signup and view all the answers

What generally needs to be evaluated to determine moral actions in consequentialism?

Possible alternative consequences Signup and view all the answers

What aspect of moral theory does deontology emphasize?

Adherence to rules or duties Signup and view all the answers

Study Notes

Diagnostic Process

History (patient's situation, past medical history, lifestyle and social factors, ICE)
Examination (general assessment, focused on specific body systems)
Differential Diagnosis (listing potential causes for the patient's symptoms)
Investigations (lab tests, imaging, etc.)
Diagnosis (determination of the cause of the symptoms)
Management (treatment plan based on the diagnosis)

Uses of Investigations

Diagnosis (confirming or ruling out potential causes)
Screening (identifying conditions in people without symptoms)
Suitability for Treatment (assessing if a treatment is appropriate)
Monitoring of Treatment (tracking the effectiveness of treatment)
Prognosis (predicting the likely course of the disease)

Appropriate Use of Investigations

Relevance (must be relevant to the patient's condition)
Accuracy (reliable and precise)
Clinical Context (considering the patient's overall health and circumstances)
Risk vs. Benefit (balancing potential risks of the investigation with the potential benefits)
Least Invasive First (starting with minimally invasive tests and progressing to more complex ones)

Biochemistry: Liver Blood Tests

Many liver proteins are measured in blood to assess liver function.
Tests can indicate liver disease, liver involvement in other conditions, and medication effects.
Various tests differentiate liver disorders and gauge damage severity.
Some tests measure liver functionality while others assess cellular integrity.
Specific liver blood tests include:
- Albumin (detects decreased levels in chronic liver disease)
- Aminotransferases (high levels indicate liver damage)
- Bilirubin (elevated levels suggest liver disease)
- Alkaline Phosphatase (increased levels indicate viral hepatitis)
- Gamma Glutamyl Transferase (increased levels indicate hepatitis and chronic liver disease)

Biochemistry: Urea and Electrolytes

Sodium (influences water balance)
Potassium (major intracellular cation, raised levels indicate renal impairment)
Urea (indicates kidney function)
Creatinine (indicates kidney function)
eGFR (estimated glomerular filtration rate, calculated from creatinine and other factors)

Haematology: Full Blood Count

Haemoglobin (Hb) (concentration of haemoglobin in blood, reduced in anemia)
Haematocrit / PCV (proportion of blood volume made up of cells)
Red Cell Count (RCC) (estimates red blood cell number, differentiates anemia types)
Mean Corpuscular Volume (MCV) (average red blood cell volume, changes in size indicate anemia types)
Mean Corpuscular Haemoglobin (MCH) / Mean Corpuscular Haemoglobin Concentration (MCHC)
White Blood Cells (WBC) / Platelets

Histopathology

Microscopic examination of tissue samples from biopsy, surgery, or autopsy.
Samples are prepared by cutting, fixing, and staining (most common is Hematoxylin and Eosin (H&E)).
Detects cellular changes like metaplasia and neoplasia.
Detects increased presence of cells not normally found in the tissue (e.g., those associated with inflammation).

Microbiology

Samples: Swabs (pus, skin, nose, throat, urethra, vagina), Body fluids (pus, urine, feces, blood, CSF), Body tissues (biopsies).

Microscopy, Culture, and Sensitivities

Primarily for bacteria or fungi.
Microscopy uses specific stains like Gram stain.
Culture media are selective for specific bacteria.
Antibiotic sensitivity testing is done using discs on culture.
Biochemical profiling of isolates provides more precise information.

Antigen Detection Tests

Antigens are molecules that trigger immune responses (antibody production).
Detection of specific antigens is used for rapid and early detection of pathogens.
Antibodies against specific antigens are used in antigen detection tests.
Useful when traditional methods are not feasible.

Polymerase Chain Reaction (PCR)

Expands specific DNA sequences for detection.
Specific DNA sequences can diagnose pathogens.
'Primers' complementary to target sequences are used in PCR tests.
Useful for early detection of pathogens, especially small quantities.

Reference Ranges

Normal values vary across the population with a normal distribution.
95% of normal values lie within 2 standard deviations of the mean.
Comparing a test result to the average is limited.
Normal range is usually considered 2 standard deviations from the mean.

Conclusions

Order tests only when clinically necessary.
Understand the reference range for the test.
Interpret results within the clinical context.
Recognize limitations in test results.

Osmolarity and Osmolality

The concentration of osmotically active particles (particles which exert an osmotic pressure) in a solution.
Osmolarity is measured per litre of solution (mOsm/L).
Osmolality is measured per kg of water (mOsm/kg).
A lower osmolarity/osmolality indicates a lower concentration of osmotically active particles.
A higher osmolarity/osmolality indicates a higher concentration of osmotically active particles.

Tonicity

Describes how one solution affects the movement of water by osmosis into or out of another solution separated from it by a semi-permeable membrane.
Determined by the relative osmolarities of the two solutions.
If two solutions have the same osmolarity, they have the same osmotic pressure and there is no net movement of water by osmosis.
These solutions are isotonic.
If two solutions have a different osmolarity, there will be an osmotic pressure difference and there will be a net movement of water by osmosis.

Tonicity in context

Tonicity is often described relative to normal plasma.
Saliva is hypotonic, meaning it has a lower osmolarity relative to normal plasma.

Composition of Saliva

Water
High concentration of some electrolytes:
- Potassium (K+)
- Bicarbonate (HCO3-) - Helps maintain an alkaline environment.
Low concentration of some electrolytes:
- Sodium (Na+)
- Chloride (Cl-)
Mucous - Provides lubrication.
Digestive enzymes - Salivary α-amylase and lingual lipase.
Antibacterial agents - Proteolytic enzymes such as lysozyme, antibodies (IgA).

Salivary Glands

Exocrine glands.
Parotid gland - Secretes serous saliva, which is watery and rich in α-amylase.
Sublingual gland - Secretes mostly mucous saliva.
Submandibular gland - Secretes mixed serous and mucous saliva.
Many tiny buccal glands.
Von Ebner’s glands of the tongue secrete lingual lipase.

Histological Structure of Major Salivary Glands

Compound (branched) tubuloacinar glands.
Secretory portion: Acinar cells
- Serous cells - Secrete α-amylase and immune components.
- Mucous cells - Secrete mucin, which becomes mucus.
Myoepithelial cells - Contract to compress acinus, forcing saliva into ducts.
Branching duct system
- Small intercalated ducts - Lined by simple cuboidal epithelium and myoepithelial cells.
- Striated ducts - Lined by simple cuboidal to simple columnar epithelium.
- Terminal (principle) duct - Empties into the oral cavity.

Saliva Production - Primary Secretion

Acinar cells secrete the initial saliva.
Initial saliva is isotonic and has a similar electrolyte concentration to plasma.

Saliva Production - Ductal Modification

Transporters on luminal and basolateral membranes of ductal cells enable modification of initial saliva.
Absorption of sodium chloride is greater than secretion of potassium and bicarbonate, leading to a net absorption of solute.
Ductal cells are relatively impermeable to water, resulting in a hypotonic solution.

Effect of Flow Rate

The degree of modification is dependent on flow rate.
Bicarbonate (HCO3-) secretion is selectively stimulated, so its concentration increases with increasing flow rate.

Taste (Gustation)

5 taste classifications: sweet, sour, bitter, salty, and umami.
Taste buds are found on the tongue, palate, larynx, and pharynx.
Taste buds in the tongue are located in taste papillae.
Taste buds contain:
- Taste receptor cells.
- Supporting cells.
- Basal cells.

Taste Receptor Cells

Taste receptor cells are chemoreceptors that detect chemical signals.
Microvilli provide a large surface area.
Tastant molecules bind to receptors or enter taste receptor cells, leading to depolarization.
Appreciation of flavour involves olfaction (smell) as well.

Mastication

Physical digestion.
Breaks down food into small pieces.
Increases surface area for enzyme action.
Mixes food with saliva.
Creates bolus for swallowing.
Structures involved:
- Teeth.
- Tongue.
- Mandible.
- Temporomandibular joint.
- Muscles of mastication.

The Pharynx

Muscular tube that connects the nasal cavity, oral cavity, larynx, and oesophagus.
Three parts:
- Nasopharynx - Posterior to the nasal cavity.
- Oropharynx - Posterior to the oral cavity.
- Laryngopharynx - Posterior to the larynx.

Muscles of the Pharynx

Inner longitudinal layer - Shortens, elevates, and widens the pharynx during swallowing.
External circular layer (pharyngeal constrictors) - Contract sequentially to force the bolus through the pharynx and into the oesophagus.
Cricopharyngeus - Upper oesophageal sphincter.

Lower Oesophageal Sphincter (LOS)

Physiological sphincter at the gastro-oesophageal junction.
Prevents reflux of gastric contents into the oesophagus.

Components of LOS

Intrinsic component - Smooth muscle.
Extrinsic component - Right crus of the diaphragm ("pinch-cock").
Other components:
- Acute angle at which the oesophagus enters the stomach.
- Mucosal folds present at the gastro-oesophageal junction ("cork in a bottle").

Gastro-oesophageal Reflux Disease (GORD)

Refux of stomach contents through the LOS into the oesophagus.
Occurs due to impairment of normal anti-reflux mechanisms, for example:
- Increased frequency of transient lower oesophageal sphincter relaxations.
- Increased intra-abdominal pressure (e.g. pregnancy, obesity).
- Low LOS pressure (e.g. due to smoking).
- Hiatus hernia.
Can cause inflammation of the oesophageal mucosa (oesophagitis).
Symptoms include:
- Heartburn.
- Acid brash.

Complications of GORD

Oesophageal stricture - Scarring and narrowing of the oesophagus.
Barrett's oesophagus - Metaplasia of squamous epithelium of the oesophagus to gastric mucosa (columnar epithelium). It has an increased risk of oesophageal cancer.

Swallowing

Oral phase (1 second) - Voluntary.
Pharyngeal phase (1 second) - Involuntary.
Oesophageal phase (10 seconds) - Involuntary.

Oral Phase

The tongue moves the bolus back towards the oropharynx.
Somatosensory receptors, including mechanoreceptors, send afferent information to the swallowing centre in the medulla (in the brainstem) via the vagus (CN X) and glossopharyngeal (CN IX) nerves.
This initiates the involuntary swallowing reflex.
Motor information is sent to the muscles of the pharynx and upper oesophagus.

Pharyngeal Phase

Soft palate elevates.
Glottis closes and larynx elevates.
Respiration is inhibited.
Epiglottis tilts to cover the laryngeal opening.
Upper oesophageal sphincter relaxes.
Peristaltic wave of contraction propels the bolus into the oesophagus.

Oesophageal Phase

Upper oesphageal sphincter closes.
Larynx falls, glottis opens, and respiration recommences.
Primary peristatic wave - Mediated by the swallowing reflex.
Lower oesophageal sphincter relaxes.
Secondary peristatic wave - Stimulated by mechanoreceptors in the wall of the oesophagus, mediated by the enteric nervous system.

Dysphagia

Difficulty with swallowing.
Potential causes:
- Mouth: Cleft lip or palate, mouth cancer.
- Pharynx: Pharyngeal cancer, tonsillitis, pharyngeal pouch.
- Oesophagus: Oesophageal cancer, achalasia, gastro-oesophageal reflux disease leading to oesophageal stricture.
- Neurologic: Parkinson's disease, stroke, head injury, dementia.

Assessment of Swallowing

History and examination.
Speech and Language Therapy (SLT):
- Clinical assessment.
- Bedside swallow test.
- Instrumental assessment.
Investigations:
- Endoscopy.
- Barium swallow.
- Manometry.

Nutrition and Energy Balance

Nutrition refers to the intake of food in relation to the body's dietary needs.
Good nutrition involves a balanced diet combined with regular physical activity, which is crucial for good health.
Malnutrition occurs when a person's diet lacks sufficient nutrients or the right balance of nutrients.
It can involve either too much or too little of certain nutrients.

Essential Nutrients

Essential nutrients are categorized into macronutrients and micronutrients.

Macronutrients

Macronutrients are required in large quantities.
Carbohydrates provide energy, regulate glucose and insulin metabolism, and influence cholesterol and triglyceride levels.
Lipids (fats) act as energy stores, regulate cell signaling, provide insulation and protection, and aid digestion.
Proteins are essential for cell and tissue growth and maintenance, gene expression, hormone production, antibody synthesis, digestion, muscle contraction, and movement.

Micronutrients

Micronutrients are required in small quantities.
Vitamins are organic compounds necessary for normal growth and nutrition, and cannot be synthesized by the body.
Minerals are inorganic elements that are essential for various bodily functions.

Vitamins

Vitamins are classified as either water-soluble or fat-soluble.
Water-soluble vitamins include B1 (thiamine), B2 (riboflavin), B3 (niacin), B5 (pantothenic acid), B6 (pyridoxine), B7 (biotin), B9 (folate), B12 (cobalamin), and C (ascorbic acid).
Fat-soluble vitamins include A (beta-carotene, retinols, retinals), D (cholecalciferol, ergocalciferol), E (tocopherols, tocotrienols), and K (phylloquinone, menadiones, menaquinones).
Vitamin B9 (folate) is particularly important during pregnancy to prevent neural tube defects.
Vitamin C deficiency leads to scurvy.
Vitamin D deficiency can cause rickets in children and osteomalacia in adults.
Vitamin D is mainly obtained through sunlight exposure.

Minerals

Minerals are essential for various bodily functions.
Iron is a component of hemoglobin, involved in oxygen transport.
Calcium is essential for bone and teeth development, as well as nerve and muscle function.
Zinc is involved in enzyme activity and immunity.
Magnesium plays a role in metabolism, nerve and muscle function.
Potassium is crucial for fluid balance, nerve and muscle function.

Iron Deficiency

Iron deficiency is a common health issue worldwide, including developed countries.
It can lead to iron deficiency anemia.
Common causes include heavy menstrual bleeding, gastrointestinal bleeding, inadequate diet, and malabsorption issues.

Hypocalcemia

Hypocalcemia is a common health issue worldwide, including developed countries.
It can result from various causes, such as hypoparathyroidism, vitamin D deficiency, chronic liver disease, chronic kidney disease, acute kidney injury and many more.

Energy Balance

Energy balance refers to the relationship between calories consumed and calories expended.
Calories in > calories out = weight gain.
Calories in = calories out = stable weight.
Calories in < calories out = weight loss.

Energy Expenditure

Basal metabolism is the energy required to sustain basic bodily functions at rest.
It includes activities such as maintaining body temperature, supporting vital systems, and essential metabolic processes.

Basal Metabolic Rate (BMR)

BMR is calculated using formulas that take into account weight, height, age, and gender.
BMR is higher in men than in women.
BMR declines with age.

Nutritional Information

Dietary intake should be monitored to ensure adequate nutrient intake and maintain energy balance.

Endocrinology

The branch of physiology and medicine that focuses on endocrine glands and hormones.
Endocrinology is the science that explores the structure and function of the endocrine system.
An endocrinologist is a physician specializing in treating disorders related to the endocrine system.

Endocrine Glands

Secrete hormones into the bloodstream, which carry them to distant targets.
Hormones are molecules released in one part of the body that regulate the activity of cells in other parts of the body.
Exocrine glands secrete products into ducts that open onto an epithelium.

Paracrine and Autocrine Signaling

Paracrine signaling involves a substance secreted by a cell that acts on adjacent cells.
Autocrine signaling involves a substance secreted by a cell that acts on the same cell by binding to surface receptors.

Endocrine System

Integrates organ function through chemicals secreted from endocrine tissues or glands into the extracellular fluid.
These chemicals, called hormones, travel through the blood to target tissues where they are recognized by specific high-affinity receptors.
Receptor molecules allow target cells to detect a unique hormonal signal amidst other chemicals in the blood.

Specificity and Selectivity of Hormone Receptors

Hormone receptors are highly specific and selective, meaning they only recognize and bind to their corresponding hormones.

Endocrine Organs and Their Functions

Hypothalamus: Produces antidiuretic hormone (ADH), which acts on the kidney to regulate fluid balance.
Pituitary: Secretes numerous hormones, including growth hormone and oxytocin, which regulates other glands.
Thyroid: Produces thyroxine, a hormone that regulates metabolism.
Pancreas: Produces insulin and glucagon, hormones that regulate blood sugar.
Adrenal: Produces epinephrine, a hormone that influences heart rate and blood pressure.
Testes: Produces testosterone, a hormone that regulates sperm production and male characteristics.
Ovaries: Produces estrogen and progesterone, hormones that regulate eggs and female characteristics.

Hormones

Play a vital role in regulating physiological processes by influencing target cell responses.
Three main classes of hormones:
- Proteins and polypeptides: Secreted by the anterior and posterior pituitary, pancreas, and parathyroid gland, among others.
- Steroid hormones: Synthesized from cholesterol, including cortisol, aldosterone, and sex hormones.
- Amines: Derived from tyrosine, including thyroid hormones and catecholamines.

Steroid (or Thyroid) Hormone Mechanism

Diffuses across the cell membrane and binds to its receptor.
The hormone-receptor complex enters the nucleus and forms a dimer.
These dimers bind to steroid-responsive elements (SREs) of DNA, initiating DNA transcription.
New messenger RNA is produced, leaves the nucleus, and is translated to synthesize new proteins.
The synthesized proteins have specific physiological actions.

Pathways of Hormone Action

Water-soluble hormones: Cannot diffuse through the cell membrane and must bind to surface receptors.
Receptors: Initiate a cell-signaling pathway within the cell involving G proteins, adenylyl cyclase, secondary messengers (cyclic AMP or cAMP), and protein kinases.
Protein kinases: Phosphorylate proteins in the cytoplas which activates proteins that carry out the changes specified by the hormone.

Endocrine Regulation: Feedback Control

Negative feedback: The most common principle for regulating hormone secretion.
- A hormone's actions directly or indirectly inhibit further secretion of the hormone.
- For example, parathyroid hormone, secreted in response to low serum calcium levels, acts on bone, kidney, and intestine to raise calcium levels, which, in turn, decreases parathyroid hormone secretion.
Positive feedback: Rare and explosive, self-reinforcing, and self-limiting.
- A hormone's actions directly or indirectly cause more secretion of the hormone.
- For example, the surge of luteinizing hormone (LH) just before ovulation is driven by positive feedback of estrogen on the anterior pituitary, leading to more estrogen production.

Adrenocorticotropic Hormone (ACTH)

Stimulates the adrenal cortex to secrete corticosteroid hormones like cortisol.
ACTH release is regulated by corticotropin-releasing hormone (CRH) from the hypothalamus in response to normal physiological rhythms.

Hormones of the Adrenal Cortex

The adrenal cortex produces three main groups of steroid hormones:
- Mineralocorticoids: Affect body minerals, particularly sodium and potassium, crucial for fluid and electrolyte balance.
  - Aldosterone is the primary mineralocorticoid, regulating sodium and potassium excretion in urine, sweat, and saliva.
- Glucocorticoids: Influenced by glucose metabolism; primarily cortisol.
  - Contribute to stress response by promoting the breakdown of stored nutrients for energy, while inhibiting tissue building.
- Sex hormones: Include androgens and estrogens, produced in smaller amounts compared to the gonads.

Synthesis and Secretion of ACTH

The gene responsible for ACTH synthesis initially produces a larger protein, a preprohormone called proopiomelanocortin (POMC).
POMC is a precursor not only to ACTH but also to other peptides like melanocyte-stimulating hormone (MSH), β-lipotropin, β-endorphin, and others.

Metabolic Actions of Cortisol

Glucocorticoids enhance gluconeogenesis by:
- Increasing protein catabolism in muscles, providing amino acids for gluconeogenesis.
- Decreasing glucose utilization and insulin sensitivity in adipose tissue, increasing glucose availability.
- Increasing lipolysis, releasing glycerol for gluconeogenesis.

Carbohydrates

Carbohydrates include sugars and starches.
General molecular formula is [C(H2O)]n.
Classified according to the number of monomers:
- Monosaccharides (1 monomer)
- Disaccharides (2 monomers)
- Oligosaccharides (3-10 monomers)
- Polysaccharides (>10 monomers)
Polysaccharides are the most common type in a healthy diet and must be broken down for absorption.
Monosaccharides end in "-ose" and are classified by:
- Number of carbon atoms: triose (3), tetrose (4), pentose (5), hexose (6)
- Isomer: Same atoms, different 3D arrangement (Ketone vs. Aldehyde and D-isomer vs. L-isomer)
- Examples of hexoses: glucose, fructose, and galactose.
Monosaccharides with long chains (pentoses, hexoses) form cyclic molecules:
- Ribose
- Glucose
Important Monosaccharides:
- Trioses: dihydroxyacetone phosphate and glyceraldehyde-3-phosphate are important intermediates in energy metabolism
- Pentoses: ribose (RNA) and deoxyribose (DNA)
- Hexoses: glucose, fructose, and galactose
Important Disaccharides:
- Sucrose: Glucose + fructose
- Lactose: Galactose + glucose
- Maltose: Two glucoses
Important Poly/Oligosaccharides:
- Starch: 75% amylopectin (branched glucose polymer, α-1,4 and α-1,6 glycosidic bonds) and 25% amylose (linear glucose polymer, α-1,4 glycosidic bonds only).
- Cellulose: Linear glucose polymer, not digestible by humans.
- Glycogen: Extensively branched glucose polymer.
- Dextrin: Branched oligomer of glucose.

Lipids

Main types: Fatty acids, triglycerides, cholesterol, cholesterol esters.
Fatty acids are hydrocarbon chains:
- Long chain (>12C)
- Very long chain (>22C)
- Saturated or unsaturated (at least one C=C double bond)
- Can be joined to glycerol to form triglycerides.
Fatty Acid Nomenclature:
- Descriptive nomenclature: C#1:#2(Δ#,#...)
- ω-# (‘omega-#’) nomenclature describes the position of the final double bond.
cis vs trans Fatty Acids:
- Cis fatty acids pack less closely than trans ones, leading to more fluid membranes.
Modified Lipids:
- Phospholipids: Phosphate group attached to one or more fatty acid chains via glycerol or sphingosine.
- Glycolipids: Carbohydrate element attached to one or more fatty acid chains, directly or via glycerol or sphingosine.
- Both are important components of cellular membranes.
Ketone Bodies:
- Small, water-soluble fatty acids formed by the liver during fasting.
- Acetoacetic acid, β-hydroxybutyric acid, and acetone are the main ketone bodies.

Roles of Lipids

Fuels (substrates for energy metabolism) for cells: fatty acids, ketone bodies
Energy storage: triglycerides
Transport between tissues: cholesterol esters, triglycerides
Structural components of cell membranes: phospholipids, cholesterol
Chemical messengers: steroids, diglycerides

Energy Release

Oxidation reactions release energy from organic molecules.
Oxidation is the loss of electrons.
Reduction is the gain of electrons.
The more carbon/hydrogen and less oxygen, the more scope for oxidation.

Lipoproteins

Transport lipids through aqueous environments (e.g., blood plasma).
Hydrophobic core: triglycerides, cholesterol esters
Hydrophilic surface: phospholipids, free cholesterol, proteins (apolipoproteins)
Classified by their densities: separated by ultracentrifugation.
Lipoprotein lipase releases fatty acids from chylomicrons and VLDLs into the tissues.

Lipoprotein Transport

Chylomicrons: Highest triglycerides, lowest cholesterol, deliver dietary triglycerides to peripheral tissues.
VLDLs: High triglycerides, low cholesterol, deliver endogenous triglycerides to peripheral tissues.
LDLs: Low triglycerides, highest cholesterol, deliver cholesterol to peripheral tissues and liver.
HDLs: Lowest triglycerides, high cholesterol, deliver cholesterol from peripheral tissues to the liver for elimination.

Glucose Transporters

Transporters: GLUT-1, GLUT-2, GLUT-3, GLUT-4, GLUT-5, SGLT-1
Affinity: Km (mM)
Specificity
Tissue distribution
Comments

Insulin Sensitivity of GLUTs

GLUT-2: Not insulin-sensitive
GLUT-4: Insulin-sensitive
GLUT-1, GLUT-3, GLUT-5, SGLT-1: Not insulin-sensitive
GLUT-2: Glucose sensing (low affinity), liver, pancreatic β-cell
GLUT-4: Insulin-sensitive glucose uptake, muscle (Sk, Card), adipose

Dietary History Limitations

Dietary history information can be unreliable, as clients may find it awkward to disclose details
Data collection should be sensitive, considering potential client discomfort in discussing personal habits
24-hour diet recall may not provide an accurate snapshot of typical dietary intake for the individual
Difficulty accurately quantifying food intake (e.g., portion sizes)

Challenges Taking a Dietary history

Clients may feel uncomfortable disclosure due to embarrassment, social stigma, or other factors
The 24-hour recall may not accurately represent daily eating habits

Healthy Diet and Homeostasis

Proper nutrition is essential for maintaining normal physiological balance (homeostasis)
Folate deficiency can lead to tiredness and other health issues, posing a risk to the individual's well-being
A balanced diet is crucial for overall health and well-being.

Biopsychosocial Model and Diet

A combination of biological, psychological and social elements influence individual dietary habits and choices
Maintaining a healthy diet and lifestyle is subject to a combination of physiological, psychological, and societal factors

Facts and Values

Facts are claims about the world verifiable by empirical methods.
Values are claims about preferences, attitudes, and emotions.
Thick concepts combine both factual and evaluative content.

Assessing Claims

Factual statements can be assessed using empirical methods.
Value claims require moral theory to assess.

Moral Theories

Consequentialism: The right action results in the best overall consequences.
Utilitarianism: Maximizes utility, which typically equates to happiness.
Deontology: Focuses on duty and abiding by rules, regardless of consequences.
Virtue Ethics: Emphases the character of the person, and what a virtuous person would do in the same circumstances.

Ethical Reasoning in Clinical Practice

Three essential considerations include:
- Principles: Ethical principles that guide decision-making.
- Particulars: The specific context and facts of the case.
- Perspectives: The viewpoints of all involved parties.

Applying PPP in Practice

Example: A registrar considers having a medical student perform a lumbar puncture on a patient with suspected tuberculous meningitis.
Principles: Respect for autonomy, beneficence, and potential consequences of the decision.
Particulars: The patient's condition, the student's experience level, and the benefits of the learning opportunity.
Perspectives: The patient's expectations, family's concerns, the student's perspective, and other patients' potential concerns.

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